X-ray stereoscopic apparatus for producing alternate images of different colors on a cathode ray tube



United States Patent f) X-RAY STERESCPIC APPARATUS FOR PRO- DUCD'JGALTERNATE IMAGES 0F DIFFER- ENT CQLORS N A CATHODE RAY TUBE Fred Jl.Euler, Ellicott City, and Edward L. Webb, Baltimore, Md., assignors toWestinghouse Electric Corporation, Pittsburgh, Pa., a corporation ofPennsylvania Filed Oct. 25, 1963, Ser. No. 318,902

.. 4 Claims. (Cl. 250-60) rl`he present invention relates to X-rayapparatus, and more particularly to a stereoscopic X-ray apparatus.

Stereoscopic X-ray apparatus as heretofore proposed have beencharacterized by a certain degree of complexity including, for example,excessive duality of component devices, cumbersome image display systemswhich accommodate a viewer only from a particular yobservation positionor which limit observation to a single viewer at any one time, or whichinherently suffer from lack of brightness and/ or definition, etc. l

Accordingly, it is `one object of the present invention to provideimproved stereoscopic X-ray apparatus.

lt is another object of the present invention to provide a stereoscopicX-ray apparatus which is so displayed on a single screen as to presentstereoscopic image viewable simultaneously by a number of viewers and ofa brightness and clarity not afforded heretofore.

Other objects and advantages of the invention will become apparent fromthe following description when taken in connection with the accompanyingdrawing having a single figure showing schematically the pertinentfeatures of an illustrative embodiment of the invention.

Referring to the drawing, Vthe general features of the exemplifiedembodiment include a dual X-ray beam source 1 for directing X-ray beams2 and 3 through the object or patient 4 from' two different angularattitudes; image-producing-and-amplifying means 5 for producing on anoutput screen 6 X-ray images resultant from penetration of the patientor object 4 by the two X-ray vbeams 2 and 3; a single video camera means7 in observance of the output screen 6 of means 5 to produceclosed-circuit video-signal information to a television monitor 9 havinga picture tube 10 for display of stereo X-ray images in lateraldisplacement on its screen 11 in a manner which can be viewed directlyby viewers 12 wearing appropriate glasses with filters 13 and 14 toseparate the images respectively to the eyes of each; and a controlmeans 15 for effecting alternate periodic generation of the two X-raybeams 2 and 3 and corresponding alternate mutually-time-exclusivepicturization of the corresponding laterally-displaced stereo images onthe screen of the picture tube 10.

The dual-X-ray beam source 1, as illustrated, is in the form of a singleX-ray tube having dual cathodes 17 and 18 and a common anode 19 toproduce the two sepa-rated, relatively-angulated beams 2 and 3 duringconduction between such anode and cathodes, together with two controlgrids 21 and 22 for controlling conduction respectively to the twocathodes. Per the usual technique, as is well known in the art, a highvoltage and cut-off bias source generator 23 is employed in connectionbetween cathodes and anodes for conduction therebetween upon adjustmentof the cut-off bias supply to the grids 21 and 22. By applyingout-of-phase square wave pulses 25 and 26 from pulse generators 27 and28 to the grids 21 and 22 the cathodes 17 and 18 are made to conductalternately to produce the X-ray beams 2 and 3 alternately at regularintervals. By employment of the image-producing and amplifier means 5,each X-ray beam 2 and 3 need not persist for longer than about twomilliseconds, and for reasons which hereinafter will become apparent,the repetition rate of each of the pulses ICC 25 and 26, and hence ofeach of the X-ray beams 2 and 3, is fifteen per second in theillustrative embodiment described herein.

The image-producing and-amplifying means 5 per se is well known in theart and includes circuit means, not shown, for energizing the well-knownimage amplifier tube 30 having an enlarged fluorescent input screen 31receiving the X-rays from the two beams 2 and 3 after passing throughthe object or patient 1, as well as the brightened image-display oroutput screen 6, which is of reduced size relative to input screen 31.Such an image amplifier tube has a brightness amplification in excess of3000 over a conventional fluorescent screen. Each X-ray pulse image willpersist on the screen 6 of the tube 30 for a period of no more thanone-thirtieth of a second.

The camera means 7 includes a camera tube 35 preferably of the type,such as the image orthicon, which is relatively sensitive and capable ofresponding to what may be moving light images on the screen 6 t-o fill aframe on the television monitor 9 at the standard rate of thirty framesper second, or, in other words, at the scanning time of one-thirtieth ofa second per frame, with clearly defined images. Camera means 7 is ofthe conventional construction such as is used for black-andwhitesingle-kinescope-tube monitors and includes the usual sync generator 37and camera control circuitry 38 as well as camera output line 39 forsupply video and sixty-cycle blanking signals for the monitor 9.

The tube 10 of monitor 9 is a commercially available color picture tubehaving the usual two guns 40 and 41, respective to such as the red andgreen dots on a tri-color shadow mask screen, and a third gun 42,respective to the third color, which third gun is ignored for purposesof the present invention. The cathodes 43 of the two 40 and 41 areconnected to branches of the camera output line 39 to simultaneouslyreceive the same signal information from the camera means 7, whichincludes the periodic video-information signals corresponding to bothX-ray beam pulses. The guns 40 and 41, however, are caused to conductalternatively in synchronism with the pulsation of the two X-ray beams 2and 3 produce alternate images on the screen 11, first of one Vcolor andthen the other, which represent the X-ray images produced by the tworelatively-angulated X-ray` beams, and are separated laterally on thecolor tube screen. When viewed by one or more observers 12 wearingfilters 13 and 14 of respective colors, red and green, for example, thealternate laterally-displaced color images become separated respectivelyto the eyes of each observer and a stereo effect results.

The monitor 9 as exemplified herein is a color monitor which includesthe well-known deflection coil means 16 and conventional circuitry 20including such as high voltage supply, video amplifier, horizontal andvertical sweep generators, filament current supply, etc., which normallycause simultaneous scanning of the beams from the three guns 40, 41, 42to scan the screen 11 twice in one-thirtieth of a second to fill a framewith two interlaced scans. As will be appreciated from precedingremarks, however, one gun 42 for example, is deactivated and the usualsimultaneous scanning from the remaining guns 40 and 41 are insteadscanned alternately at consecutive one-thirtieth second periods byvirtue of the cut-off bias control pulses supplied to their grids 48 inaccord with the modification of such color monitor as advanced by theillustrative embodiment of the present invention described herein.

In behalf of simplification, the alternate cut-off of the respectivecolor beams of the color picture tube 10 and of the X-ray beams 2 and 3of tube 1 are synchronized by the sixty-cycle sync signal produced bythe sync generator affiliated with the video camera means 7 forcontrolling vertical beam drive in the monitor. To produce bias pulsessuitable for such control, the sixtycycle sync signals from syncgenerator 37 are fed to a two stage divider or flip-Hop which producessquare wave pulses 50, 51 each of one-thirtieth second duration at afifteen cycle repetition rate in two output 52 and 53, respectively; thepulses 50 being 1807 out of phase with the pulses 51. Outputs 52 and 53are connected to the grids 48 of guns 40 and 41, respectively, and thepulses 50 and 51 cause these guns to conduct alternately at periods ofone-thirtieth second each, to give thirty frames per second on the colorpicture tube screen.

At the same time, the square wave pulses 50 and 51 in outputs 52 and 53are tapped by respective branches differentiated by respectivecapacitors 55 and 56 to produce differentiated pulses 57 and 58 fed tothe aforementioned pulse generators 27 and 28 to produce the dual-beamX-ray tube-conduction-control pulses 25 and 26 aforedescribed.

Although the preceeding is a description of an illustrative embodimentof the invention, it will be understood that the spirit and scope ofsuch invention embraces modifications which will occur readily to thoseversed in the art, and that therefore such invention should beinterpreted to cover such modifications as lie within the spirit andscope of the appended claims.

What is claimed is:

1. Stereoscopic X-ray apparatus comprising X-ray source means operableto radiate X-rays to an object from two different angles alternately,means producing electrical signals corresponding to alternate X-rayimages of such object respective to said two different angles, means,including a cathode ray tube productive of two images of differentcolors, respectively, on its screen respective to two signal inputs, andmeans for effecting such alternating operation of said X-ray sourcemeans and for rendering said two signal inputs alternately responsive tosaid electrical signals correspondingly with alternation of X-'rayradiation angles, whereby two horizontally spaced apart images arealternately presented on the cathode ray tube screen in respectivecolors which may be separated respective to the eyes of a viewer bycolor filter eye glasses.

2. Stereoscopic X-ray apparatus comprising X-ray source means operableto radiate X-rays to an object at two different angles alternately;means for producing light images of X-ray images of such object; ablackand-white video camera means productive of video signalscorresponding to such light images and including a sync generatorproductive of sixty-cycle blanking signals for a video monitor; a videomonitor, including a multi-gun color picture tube productive ofdifferent colors on the screen of such tube by respective electronbeams, operable to scan such beams in synchronism with the aforesaidsixty-cycle blanking signals to fill a frame on the screen eachone-thirtieth of a second, and operable to respond to video signals fromsaid camera means to modulate such electron beams to produce colorimages; and control means regulated by said sixty-cycle blanking signalsto effect the alternate different-angled radiation of X-rays at a rateof thirty pulses per second and to effect alternate response of two ofthe electron beams to video signals from said 4camera means respectivelyto the angles of X-ray radiation, whereby images of the observed objectare alternately presented on the screen of said color picture tube athorizontally offset positions in accord with the different angles ofX-ray radiation and in respective colors which may be separated by theviewer for stereo effect with use of two-color eye glasses.

3. The X-ray apparatus of claim 2, wherein said means for producinglight images includes an image amplifier tube, and the X-ray sourcemeans is controlled to generate X-rays only for intervals substantiallyless than the time required to fill a frame on the screen of the colorpicture tube.

4. Stereoscopic X-ray apparatus as set forth in claim 2, wherein saidcontrol means comprises a two-stage nip-flop circuit which convertssixty-cycle blanking pulses to two out-of-phase fifteen cycle squarewaves for biasing cut-off control of the electron beams in the colorpicture tube, capacitors for converting samples of said square waves torespective differentiated pulses, and pulse generators for convertingsaid differentiated pulses to respective out-of-phase bias pulses forcontrolling alternation, rate and conduction time of the X-ray sourcemeans.

References Cited by the Examiner UNITED STATES PATENTS Re. 21,96412/1941 Leishman 250-60 1,995,054 3/1935 Chambers Z50-60 2,730,566l/l956 Bartow et al. 178-6.5 3,004,101 10/1961 Jacobs et al. 178-6.8

RALPH G. NILSON, Primary Examiner.

A. L. BIRCH, Assistant Examiner.

2. STEREOSCOPIC X-RAY APPARATUS COMPRISING X-RAY SOURCE MEANS OPERABLETO RADIATE X-RAYS TO AN OBJECT AT TWO DIFFERENT ANGLES ALTERNATELY;MEANS FOR PRODUCING LIGHT IMAGES OF X-RAY IMAGES OF SUCH OBJECT; ABLACKAND-WHITE VIDEO CAMERA MEANS PRODUCTIVE OF VIDEO SIGNALSCORRESPONDING TO SUCH LIGHT IMAGES AND INCLUDING A SYNC GENERATORPRODUCTIVE OF SIXTY-CYCLE BLANKING SIGNALS FOR A VIDEO MONITOR; A VIDEOMONITOR, INCLUDING A MULTI-GUN COLOR PICTURE TUBE PRODUCTIVE OFDIFFERENT COLORS ON THE SCREEN OF SUCH TUBE BY RESPECTIVE ELECTRONBEAMS, OPERABLE TO SCAN SUCH BEAMS IN SYNCHRONISM WITH THE AFORESAIDSIXTY-CYCLE BLANKING SIGNALS TO FILL A FRAME ON THE SCREEN EACHONE-THIRTIETH OF A SECOND, AND OPERABLE TO RESPOND TO VIDEO SIGNALS FROMSAID CAMERA MEANS TO MODULATE SUCH ELECTRON BEAMS TO PRODUCE COLORIMAGES; AND CONTROL MEANS REGULATED BY SAID SIXTY-CYCLE BLANKING SIGNALSTO EFFECT THE ALTERNATE DIFFERENT-ANGLED RADIATION OF X-RAYS AT A RATEOF THIRTY PULSES PER SECOND AND TO EFFECT ALTERNATE RESPONSE OF TWO OFTHE ELECTRON BEAMS TO VIDEO SIGNALS FROM SAID CAMERA MEANS RESPECTIVELYTO THE ANGLES OF X-RAY RADIATION, WHEREBY IMAGES OF THE OBSERVED OBJECTARE ALTERNATELY PRESENTED ON THE SCREEN OF SAID COLOR PICTURE TUBE ATHORIZONTALLY OFFSET POSITTIONS IN ACCORD WITH THE DIFFERENT ANGLES OFX-RAY RADIATION AND IN RESPECTIVE COLORS WHICH MAY BE SEPARATED BY THEVIEWER FOR STEREO EFFECT WITH USE OF TWO-COLOR EYE GLASSES.